Rheumatoid arthritis is a progressive, systemic autoimmune disease characterized by synovitis that damages diarthroidal joints and is accompanied by fatigue, anemia, and osteopenia. Rheumatoid arthritis has a prevalence of 0.5% to 1.0% (Silman, A. J. “Epidemiology and the rheumatic diseases.” In: Maddison P J, Isenberg D A, Woo P, Glass D N, eds. Oxford Textbook of Rheumatology: Oxford University Press: 499-513 (1993)) and a peak incidence between 40 and 60 years of age and affects primarily women. The cause of RA is not known; however, certain histocompatibility antigens are associated with poorer outcomes. Nonsteroidal anti-inflammatory drugs (NSAIDs) provide only symptomatic relief. Disease-modifying antirheumatic drugs (DMARDs), the cornerstone of RA treatment throughout all stages of the disease (Maddison et al., supra), maintain or improve physical function and retard radiographic joint damage (Brooks, P. M. “Clinical Management of rheumatoid arthritis.” Lancet 341: 286-290 (1993)). More recently, biological compounds that target tumor necrosis factor alpha (TNF-α), B-cells, or T-cells have been used successfully to treat RA, but ˜30% to 40% of patients fail to respond to these therapies (Bathon et al. New Eng. J. Med. 343: 1586-1592 (2000); Maini et al. Arthritis & Rheumatism 41: 1552-1563 (1998)).
Interleukin-6 (IL-6) is a proinflammatory, multifunctional cytokine produced by a variety of cell types. IL-6 is involved in such diverse processes as T-cell activation, B-cell differentiation, induction of acute phase proteins, stimulation of hematopoietic precursor cell growth and differentiation, promotion of osteoclast differentiation from precursor cells, proliferation of hepatic, dermal and neural cells, bone metabolism, and lipid metabolism (Hirano T. Chem Immunol. 51:153-180 (1992); Keller et al. Frontiers Biosci. 1: 340-357 (1996); Metzger et al. Am J Physiol Endocrinol Metab. 281: E597-E965 (2001); Tamura et al. Proc Natl Acad Sci USA. 90:11924-11928 (1993); Taub R. J Clin Invest 112: 978-980 (2003)). IL-6 has been implicated in the pathogenesis of a variety of diseases including autoimmune diseases, osteoporosis, neoplasia, and aging (Hirano, T. (1992), supra; and Keller et al., supra). IL-6 exerts its effects through a ligand-specific receptor (IL-6R) present both in soluble and membrane-expressed forms.
Elevated IL-6 levels have been reported in the serum and synovial fluid of RA patients, indicative of production of IL-6 by the synovium (Irano et al. Eur J Immunol. 18:1797-1801 (1988); and Houssiau et al. Arthritis Rheum. 1988; 31:784-788 (1988)). IL-6 levels correlate with disease activity in RA (Hirano et al. (1988), supra), and clinical efficacy is accompanied by a reduction in serum IL-6 levels (Madhok et al. Arthritis Rheum. 33:S154. Abstract (1990)).
Tocilizumab (TCZ) is a recombinant humanized monoclonal antibody of the immunoglobulin IgG1 subclass which binds to human IL-6R. Clinical efficacy and safety studies of intravenous (IV) TCZ have been completed or are conducted by Roche and Chugai in various disease areas, including adult-onset RA, systemic juvenile idiopathic arthritis and polyarticular juvenile idiopathic arthritis.
TCZ 8 mg/kg IV has been approved in over 70 countries for use in RA, including Japan and Europe. In the United States, TCZ IV (4 mg/kg and 8 mg/kg) has been approved in RA patients who have had an inadequate response to anti-TNF agents. Additionally, TCZ was approved for use in Castleman's disease in India and Japan.
On Apr. 15, 2011, the U.S. Food and Drug Administration approved TCZ, given alone or in combination with methotrexate, for the treatment of active systemic juvenile idiopathic arthritis (sJIA) (US Package Insert (USPI) for TCZ ACTEMRA®, April 2011). On Aug. 1, 2011, TCZ was also approved in the EU for the treatment of active sJIA who have responded inadequately to previous therapy with NSAIDs and systemic corticosteroids (CS), and TCZ can be given as monotherapy (in case of intolerance to MTX or where treatment with MTX is inappropriate) or in combination with MTX in patients 2 years of age and older (Summary of Product Characteristics (SmPC) for RoACTEMRA, Roche Registration Limited 6 Falcon Way Shire Park, Welwyn Garden City, AL7 1TW, United Kingdom, 4 Jun. 2010). The approved TCZ dose for sJIA patients weighing <30 kg is 12 mg/kg TCZ, and for patients weighing ≧30 kg is 8 mg/kg IV infusion every 2 weeks.
TCZ has been approved for treatment of polyarticular course juvenile idiopathic arthritis (pcJIA) in Japan based on the phase 3 study MRA318JP conducted in Japanese patients. WA19977 is an ongoing pivotal phase 3 study investigating the efficacy, safety, PK and PD of TCZ in children with pcJIA age of 2 to 17 years old.
TCZ has been intravenously administered to 2 Japanese patients with diffuse cutaneous systemic sclerosis (SSc) (Shima et al. Rheumatology 49:2408-12 (2010), doi:10.1093/rheumatology/keq275)), and to 5 patients with SSc (Meunier et al. Ann. Rheum. Dis. 70(Suppl 3):660 (2011)). In patients with SSc, elevated levels of circulating IL-6 have been reported, particularly in patients with early disease. IL-6 is overexpressed in endothelial cells and fibroblasts of involved skin in patients with SSc (Koch et al. Pathobiology 61:239-46 (1993)). Elevated IL-6 levels have been detected in the bronchioalveolar lavage of patients with SSc. Dermal fibroblasts from patients with SSc have been reported to constitutively express higher levels of IL-6 compared with those of healthy controls (Kadono et al. J. Rheumatol. 25:296-301 (1998)). In addition, serum IL-6 levels correlate positively with skin sclerosis and acute-phase proteins (Ong and Denton, Curr. Opin. Rheumatol. 22:264-72 (2010)).
IL-6 has first been described as a potent growth and maturation factor for developing human plasma cells. IL-6 induces B-cell proliferation, antibody secretion, and survival of plasmablasts. Activated B cells produce IL-6 and other cytokines. In patients with SSc, polyclonal B-cell activation, presence of highly specific autoantibodies, and B-lymphocyte infiltration in diseased skin of patients have been detected. However, open-label trials of B cell-depleting antibodies in patients with SSc have resulted in inconclusive data to date (Bosello et al. Arthritis Res. Therapy 12:R54 (2010); Layfatis et al. Arthritis Rheum. 60; 578-83 (2009); Daoussis et al. Rheumatology 49:271-80 (2010)). Bosello et al. (2010) reported beneficial effects of B-cell depletion for patients with SSc that were associated with a reduction of serum IL-6 levels. In addition to its effects on B-cell function, IL-6 has specific effects on T cells. IL-6 promotes T-cell survival and Th17-lymphocyte differentiation and inhibits development of regulatory T cells. Th17 cells produce IL-17 and have been linked to development of autoimmune diseases. In an autocrine loop, IL-17 may induce IL-6 synthesis in human fibroblasts (Fossiez et al. J. Exp. Med. 813:2593-2603 (1996)). Increased circulating Th17 cells have also recently been reported in patients with SSc (Radstake et al. PLoS ONE 4(6):e5903. doi:10.1371/journal.pone.0005903. Atamas S P Life Sci 72:631-43 (2009)), whereas serum and bronchioalveolar lavage levels of IL-17 were found to be increased in patients with SSc and ILD (Kurasawa et al. Arthritis Rheum 43: 2455-63 (2000)).
Fibrosis gradually replaces the inflammatory phase of SSc. In vitro experiments with human dermal fibroblast cultures showed that IL-6 increased collagen type I, glycosaminoglycans, hyaluronic acid, and chondroitin sulfate production (Duncan and Berman J. Invest. Dermatol. 97:686-92 (1991)).
Giant cell arteritis (GCA) is a primary vasculitis involving large and medium sized arteries which is typically diagnosed by temporal artery biopsy. Signs and symptoms of GCA include elevated erythrocyte sedimentation rate (ESR) or new headaches. Adverse sequelae include: irreversible blindness (bilateral retinal or optic nerve ischemia), infarcation of brain, tongue, upper limb, or aortic aneurysm. GCA is an unmet medical need. High dose corticosteroids (CS) are the current standard of care, but more durable remissions are needed (50% of patients relapse), and steroid sparing treatment options are needed in view of steroid-related complications). Case studies reporting the use of TCZ in giant cell arteritis are: Seitz et al. Swiss Med Wkly 141:w13156 pgs. E1-E4 (2011); Salvarani et al. Arth. and Rheum. (April 2011); and Beyer et al. Ann. Rheum. Dis. pgs. 1-2 (2011), doi:10.1136/ard.2010.149351. In each of these studies TCZ was administered intravenously.
Patents and patent publications related to anti-IL-6R antibodies include: U.S. Pat. No. 5,171,840 (Kishimoto), U.S. Pat. No. 5,480,796 (Kishimoto), U.S. Pat. No. 5,670,373 (Kishimoto), U.S. Pat. No. 5,851,793 (Kishimoto), U.S. Pat. No. 5,990,282 (Kishimoto), U.S. Pat. No. 6,410,691 (Kishimoto), U.S. Pat. No. 6,428,979 (Kishimoto), U.S. Pat. No. 5,795,965 (Tsuchiya et al.), U.S. Pat. No. 5,817,790 (Tsuchiya et al.), U.S. Pat. No. 7,479,543 (Tsuchiya et al.), US 2005/0142635 (Tsuchiya et al.), U.S. Pat. No. 5,888,510 (Kishimoto et al.), US 2001/0001663 (Kishimoto et al.), US 2007/0036785 (Kishimoto et al.), U.S. Pat. No. 6,086,874 (Yoshida et al.), U.S. Pat. No. 6,261,560 (Tsujinaka et al.), U.S. Pat. No. 6,692,742 (Nakamura et al.), U.S. Pat. No. 7,566,453 (Nakamura et al.), U.S. Pat. No. 7,771,723 (Nakamura et al.), US 2002/0131967 (Nakamura et al.), US 2004/0247621 (Nakamura et al.), US 2002/0187150 (Mihara et al.), US 2005/0238644 (Mihara et al.), US 2009/0022719 (Mihara et al.), US 2006/0134113 (Mihara), U.S. Pat. No. 6,723,319 (Ito et al.), U.S. Pat. No. 7,824,674 (Ito et al.), US 2004/0071706 (Ito et al.), U.S. Pat. No. 6,537,782 (Shibuya et al.), U.S. Pat. No. 6,962,812 (Shibuya et al.), WO 00/10607 (Akihiro et al.), US 2003/0190316 (Kakuta et al.), US 2003/0096372 (Shibuya et al.), U.S. Pat. No. 7,320,792 (Ito et al.), US 2008/0124325 (Ito et al.), US 2004/0028681 (Ito et al.), US 2008/0124325 (Ito et al.), US 2006/0292147 (Yoshizaki et al.), US 2007/0243189 (Yoshizaki et al.), US 2004/0115197 (Yoshizaki et al.), US 2007/0148169 (Yoshizaki et al.), U.S. Pat. No. 7,332,289 (Takeda et al.), U.S. Pat. No. 7,927,815 (Takeda et al.), U.S. Pat. No. 7,955,598 (Yoshizaki et al.), US 2004/0138424 (Takeda et al.), US 2008/0255342 (Takeda et al.), US 2005/0118163 (Mizushima et al.), US 2005/0214278 (Kakuta et al.), US 2008/0306247 (Mizushima et al.), US 2009/0131639 (Kakuta et al.), US 2006/0142549 (Takeda et al.), U.S. Pat. No. 7,521,052 (Okuda et al.), US 2009/0181029 (Okuda et al.), US 2006/0251653 (Okuda et al.), US 2009/0181029 (Okuda et al.), US 2007/0134242 (Nishimoto et al.), US 2008/0274106 (Nishimoto et al.), US 2007/0098714 (Nishimoto et al.), US 2010/0247523 (Kano et al.), US 2006/0165696 (Okano et al.), US 2008/0124761 (Goto et al.), US 2009/0220499 (Yasunami), US 2009/0220500 (Kobara), US 2009/0263384 (Okada et al.), US 2009/0291076 (Morichika et al.), US 2009/0269335 (Nakashima et al.), US 2010/0034811 (Ishida), US 2010/0008907 (Nishimoto et al.), US 2010/0061986 (Takahashi et al.), US 2010/0129355 (Ohguro et al.), US 2010/0255007 (Mihara et al.), US 2010/0304400 (Stubenrach et al.), US 2010/0285011 (Imaeda et al.), US 2011/0150869 (Mitsunaga et al.), WO 2011/013786 (Maeda) and US 2011/0117087 (Franze et al.).